JP3985529B2 - Waste plastic treatment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for effectively using plastic, cloth and wood in general waste discharged from homes.
[0002]
[Prior art]
Most of the foods purchased at supermarkets are packaged in plastic, and can be taken home in shopping bags made of plastic film. Therefore, a lot of plastics such as PVC, PP, PE, PET, ABS, PS, and a film on which aluminum is deposited are mixed in the general waste discharged from the home. In addition, many of these plastic trays and wraps are contaminated by leftovers, etc., and it is almost impossible to recycle these as recycled plastic materials, most of which have other methods than incineration. There is no actual situation.
[0003]
On the other hand, used PET bottles are relatively well separated and collected in supermarkets, etc., and are reused as molding materials or fiber materials. The current situation is in the situation.
[0004]
[Problems to be solved by the invention]
When the plastic contained in the above general waste is incinerated as municipal waste, high temperature is generated and damage to the incinerator is accelerated, and some chlorinated resins (for example, PVC are often used for wraps) )), There is a concern that chlorine gas may adversely affect the environment, and therefore, a safe and effective treatment method is a problem.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, wood such as plastic, cloth and chopsticks in general waste is pulverized and kneaded and melted by using an extrusion molding machine having two or more air vent devices. The waste resin discharged from the nozzle of the molding machine is cut into small pieces, or cast into a half mold (female mold) and molded into a solid form. The product is used as a fuel, or as an extender for higher-quality waste plastic fuel.
[0006]
The invention according to claim 2 relates to the blending of the plastic solidified fuel obtained by the molding apparatus according to claim 1, and pulverizes, melts and kneads the plastic, cloth, wood, etc. in the general waste, solidifies this, 50 to 60% by weight of PET resin and 10 to 35% by weight of thermoplastic resin (PP, PE, PS, ABS, PC, etc.) are mixed with 10 to 15% by weight of pulverized powder (piece) obtained by pulverizing The amount of heat of combustion is adjusted to approximately 6000 to 7000 kcal / kg by means of forming, and thus combustion in the furnace is possible as a substitute for coal, or it can be used as a gas reducing agent or sedative in a steelmaking melting furnace A solid fuel is obtained.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In general household waste, plastics, cloth and wood such as disposable chopsticks, paper, etc. are usually mixed in addition to leftovers. Plastic, cloth, wood (mainly chopsticks, etc.) and the like are taken out from this, pulverized, put into an extruder 11 having two or more vent devices, melt-kneaded, and extruded into a strand or a band. Or pelletized or cut into small pieces, or cast into a half mold (one-side mold) to form a solid molded product. , Trying to obtain solidified fuel with stable combustion heat quantity by mixing it as pulverized powder (pieces) of PET bottles that are industrial waste and thermoplastic plastic molded products that are not mixed with relatively different materials It is.
[0008]
FIG. 1 shows a molding apparatus 1 according to the present invention, which comprises an extruder 11 and a mold 8 (half mold on the cavity side) attached to a conveyor 2. A cylinder 13 into which a screw 12 that is rotated by a rotation drive device (not shown) is inserted has air vents 14 and 14 (preferably 3 or more) having at least two holes, and a heater 15 is divided into several zones. It is attached and the temperature of each zone can be set individually. Moreover, the nozzle 16 that discharges the molten resin M is desirably installed downward. The material thrown into the hopper 17 is discharged by being melted by the cylinder 13.
[0009]
Next, M discharged from the extrusion molding machine 11 is pelletized by a so-called hot cut method or cut into small pieces having a length of 5 to 25 mm, or solidified by the following apparatus.
[0010]
The solidification device for solidification is a side view, at least the upper surface 2a is kept horizontal, and the conveyor 2 engaged with the sprocket wheels 3 (3a, 3b) on both sides thereof is continuously or intermittently driven by a drive device not shown. Rotate to. On the side of the sprocket wheel 3a, a cam 4 having a disk shape or the like is pivotally attached to the sprocket wheel 3a so as to be rotatable coaxially with or adjacent to the sprocket wheel 3a. The nozzle 16 which is the front-end | tip of the extrusion molding machine 11 is arrange | positioned so that it may be located.
[0011]
A plurality of molds 8 (FIG. 2) having cavities 8c are continuously attached to the conveyor 2 in a substantially intimate manner in the rotational direction. An ejector 8e that protrudes from the bottom surface 8b of the mold 8 through the bottom of the mold and protrudes from the back surface is slidably inserted into the cavity 8c of the mold 8 against the pressure of the spring.
[0012]
The scraper plate 5 is installed at a position slightly closer to the moving direction of the conveyor than the nozzle 16 of the extruder 11 so that the lower end thereof is close to the upper surface of the mold 8, and further closer to the moving direction of the conveyor 2. The cooling shower 6 is installed above the position, and the water to be sprayed is sprinkled on the mold 8. Further, a pressing plate 7 is mounted on the side of the conveyor 2 in the traveling direction, that is, on the other arcuate portion (near the sprocket wheel 3a), which is close to the upper surface of the mold and prevents the molded product from being lifted. .
[0013]
A method of using the molding apparatus of the present invention having the above configuration will be described. First, plastics in general waste are put into the hopper 17 of the extrusion molding machine 11, and are melted and discharged by a cylinder. The discharged molten resin M is filled in the mold 8 that has reached the upper part of the sprocket wheel 3a sequentially as the conveyor rotates. In this case, since it is continuously discharged from the extruder and the conveyor is also continuously rotated, the molten resin M is not only in the cavity 8c but also on the mold surface between the adjacent mold cavities. Will be deposited. The accumulated molten resin is moved to the rear cavity 8c by the scraping plate 5 scratching the upper surface of the mold, and is filled in the cavity to form a molded product 9. Also by the action of the scraping plate 5, the deposited resin layer between the cavities remains as a relatively thin strip 9a.
[0014]
Thereafter, a cooling shower 6 for cooling the resin installed on the left side in FIG. 1 cools the molded product 9 by pouring water on the moving mold 8 and the resin. Further, when the mold 8 moves to the left, the outer peripheral surface of the cam 4 contacts the lower end surface of the ejector 8e. As a result, the ejector 12 rises in the cavity 8e, and the molded product 9 is projected out of the cavity. However, despite the presence of the scraper plate 5 as described above, the adjacent molded product is in a state of being connected by the thin ribbon 9a between the adjacent cavities.
[0015]
In this way, the strip-like portion 9a connecting the molded products causes a problem in separation between the molded products. Therefore, the pressing plate 7 has an effect of preventing the adjacent subsequent in-cavity molded product from rising from the cavity with the release of the molded product 9 protruded by the ejector in contact with the cam 4. As a result, the thin ribbon-like portions 9a are bent and cut.
[0016]
A water tank W is installed at the lower part of the conveyor 2, and the resin protruding from the mold cavity, that is, the molded product 9 falls into the water tank and is further cooled.
[0017]
【Example】
Selected plastics and cloth in municipal waste as general waste. The contents are very various and include, for example, plastic films such as wrapping films, aluminum vapor deposition films, foamed resin trays, bottles, toys, washbasins, buckets, flowerpots, cloths such as trousers and underwear, and pieces of wood. These were pulverized using a pulverizer or the like, or cut into small pieces with scissors to make fine pieces, which were put into the hopper 21h of the extruder 21 and melt-kneaded and extruded.
[0018]
These plastics contain moisture such as food adhering to them, or because some wrapping films are made of chlorinated resin, they may generate harmful gases such as chlorine gas as well as water vapor in the cylinder. is there. Cylinder temperature is set to 150, 200, 250, 300 ° C, for example, in order from the hopper side to the nozzle side, and the temperature is set higher in order, and the gas vented from 200 to 250 ° C or the air vent before and after that is introduced into the water. Then discharge. By this temperature setting, various resins are almost completely melted.
[0019]
The molten resin discharged from the nozzle 16 of the extrusion molding machine 11 in the form of a string or a band is immediately cut with a cutter into pellets or small pieces, or filled into a mold cavity 8c on a rotating conveyor. Is done.
[0020]
In filling the cavity 8c, the resin adhering to the upper surface portion of the mold between the cavity and the next cavity is blocked by the scraping plate 5, and most of the resin is pushed into the rear cavity, and a part of the resin is strip-shaped. As described above, the molded parts are connected as the portion 9a. The filled resin is then cooled with shower 6 water and proceeds to the left end of the conveyor apparatus. Therefore, the lower end surface of the ejector 8e projecting downward is brought into contact with the cam 4, and the molded product 9 is ejected.
[0021]
As shown in FIG. 3, the molded product protruding from the cavity is connected to the molded product in the subsequent cavity via the strip 9a, and it is necessary to separate it. As described above, when the molded product 9 is ejected by the ejector 8e, the strip 9a is bent and cut if the subsequent molded product is in the cavity and cannot be raised. The pressing plate 7 prevents the molded product from rising.
[0022]
The molded product thus cut or solidified is porous because its wood and fibers are mixed, and since it does not have a device for compressing the molten resin into the cavity, the apparent specific gravity is It was 1 g / cm ³ or less. In addition, chlorine gas is thermally decomposed to introduce chlorine gas into the water from the air vent or subjected to chemical treatment, and the molded product will not discharge harmful substances even if incinerated thereafter.
[0023]
Although it is possible to incinerate a solid molded product that has been crushed or molded as described above, the specific gravity and calorific value are generally smaller than those of coal (specific gravity is 1 g / cm or less, combustion calorie is 5000 kcal / kg or less). Therefore, when it was put into the furnace together with coal, the temperature inside the furnace could become non-uniform due to non-uniform distribution of both.
[0024]
Therefore, the molded product made of this general waste was crushed again. Further, polyethylene and polypropylene (10,500 to ˜10), which are so-called industrial wastes, in which PET resin (combustion heat 5000 to 5500 kcal / kg) 50 to 60% by weight, such as pulverized pieces of waste PET bottles, is relatively free of foreign materials. 11,000 kcal / kg) Add 30-30% by weight of pulverized powder such as PS, ABS, PC, etc., and further add 5-20% of the powder of the above-mentioned general waste or hot-cut pellets or small pieces. % And again, the mixture was melt kneaded by an extrusion molding machine having the same cylinder temperature conditions (150, 200, 250, 300 ° C.), and filled into the mold cavity through a nozzle.
[0025]
In this way, the mold filled with resin is further cooled in the cooling process and the releasing process as the conveyor rotates. The molded product thus obtained, that is, the plastic solid fuel, had a glossy surface and a specific gravity of about 1.0 to 1.1 g / cm ³ . Moreover, it has become a thing with the emitted-heat amount of about 6000-7000 kcal / kg by the said material ratio.
[0026]
【The invention's effect】
As described above, the plastic solid fuel (molded article) according to the present invention has a specific gravity of 1.1 g / cm ³ or more, and when thrown together with coal from the furnace outlet, the flight distance is almost the same as that of coal. Thus, there is no bias in the distribution with coal in the furnace.
[0027]
Further, this plastic solid fuel is almost equivalent to the calorific value (5,000 to 7500 kcal / kg) of coal, and even when mixed with coal and put into the furnace, there is no unevenness in the furnace temperature.
[0028]
The plastic solid fuel according to the present invention is uniform in quality despite containing general waste, and is effective as a reducing agent or sedative in a steelmaking blast furnace.
[Brief description of the drawings]
FIG. 1 is a side cross-sectional view of a waste plastic molding apparatus according to the present invention.
FIG. 2 is a cross-sectional view showing a pressing plate portion that is a part of FIG. 1;
FIG. 3 is a cross-sectional view showing a state where a pressing plate is not attached.
FIG. 4 is a perspective view of a molding die.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Molding device 2 Conveyor 3 Sprocket wheel 4 Cam 5 Scraping plate 6 Cooling shower 7 Press plate 8 Mold 9 Molded article 11 Extruder 12 Screw 13 Cylinder 14 Air vent 15 Heater 16 Nozzle 17 Hopper

Claims (1)

Molded by pulverizing plastics, cloth and wood in general waste and melt-kneading them with an extrusion molding machine with two or more air vent devices, extruding and cutting into small pieces, or casting into half molds The pulverized solid or solidified fuel (RDF) is further pulverized, and the pulverized material is mixed with PET or other thermoplastic resin, melt-kneaded by an extruder, cast into a half mold, and molded. To process plastics , cloth and wood into solid fuel .

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